Mixpanel

Lightweight, dependency-free, in-memory Mixpanel ingestion + query API fake for testing code that uses the real mixpanel Node SDK (and the language-agnostic Mixpanel HTTP API).

Default port: 4808

Quick start

import { MixpanelServer } from "./services/mixpanel/src/server.js";

const server = new MixpanelServer(4808);
await server.start();
// ... run your app/tests ...
await server.stop();

Point the real mixpanel client at it via the host option:

import Mixpanel from "mixpanel";

const mp = Mixpanel.init("parlel", { host: "127.0.0.1:4808", protocol: "http" });
mp.track("Signed Up", { distinct_id: "user-123", plan: "pro" });

Every ingested event is held in memory and inspectable via /__parlel/*.

Implemented operations

Ingestion uses Basic auth (project token as username); any credentials are accepted.

Ingestion

POST /track — ingest event(s). Accepts a base64-encoded data query/form param, a JSON object, or a JSON array. Returns 1 on success, 0 when nothing valid was found.
POST /import — historical ingest. Returns { code: 200, num_records_imported, status: "OK" }.
POST /engage — people profile updates ($set, $set_once, $unset). Returns 1.

Query

GET /api/2.0/events — query captured events (optional ?event=["Name"] filter). Returns { legend_size, data, events }.

Service & inspection operations (parlel extensions)

GET / — service metadata.
GET /health — health check ({ status: "ok" }).
POST /__parlel/reset — reset all state.
GET /__parlel/events — list captured events.
GET /__parlel/people — list people profiles.
DELETE /__parlel/events — clear captured events.
OPTIONS * — CORS preflight (204).

Access via MCP / preview URL

In a parlel pool the service is reachable at its preview URL (host/port shown by the pool); set the SDK's host/protocol to that URL. Through the parlel MCP server the ingestion and query routes are exposed as a tool surface, so an AI agent can drive /track, /import, /engage and query /api/2.0/events directly.

Surface coverage

This emulator faithfully replicates the API surface most application code and agents exercise. Anything below the supported lines is either an intentional design choice for a fast, zero-cost local emulator (✓ By design) or a candidate for a future release (⟳ Roadmap) — never a silent inaccuracy.

Legend: ✅ fully supported · ◐ accepted (stored, not strictly enforced) · ✓ by design · ⟳ on the roadmap.

Feature	Status
`track` (data param + JSON + array)	✅ Supported
`import` historical ingest	✅ Supported
`engage` people updates	✅ Supported
`events` query	✅ Supported
Captured-event inspection	✅ Supported (parlel extension)
JQL / segmentation / funnels / retention math	⟳ Roadmap
Real time-series aggregation	✓ By design — Not computed
Basic-auth credential validation	◐ Any credentials accepted

Manifest

See services/mixpanel/manifest.json:

name: mixpanel, image: parlel/mixpanel:1.0
port: 4808, protocol: http, healthcheck: /health, startup ≈ 100ms
env: MIXPANEL_TOKEN, MIXPANEL_API_SECRET, MIXPANEL_HOST

Configuration — `test.env`

Copy these into your test.env (used by the bridge sidecar flow). Tokens are Parlel's seeded test credentials — any non-empty value is accepted by the emulator, so you rarely need to change them. Swap in real credentials only when pointing at the live service in prod.env.

MIXPANEL_TOKEN=parlel
MIXPANEL_API_SECRET=parlel-secret
MIXPANEL_HOST=http://parlel-bridge:4808
MIXPANEL_BASE_URL=http://parlel-bridge:4808